Rotar pump or compressor



G. B. PETSCHE.

ROTARY PUMP OR COMPRESSOR.

APPLICATION FILED NOV. 2. 1920.

Patented July 12, 1921'.

A TWK/VIK often carbonizes,

UNITED STATES PATENT OFFECE.

GUSTA-V B.. PETSCHE, 0F YONKERS, NEW YORK.

nora-ar Aruine on COMPRESSOR.

Application led November 2,1920. Serial No. 421,272.

T 0 all whom t may concer/n.'

Be it known that I, GUs'rAv B. PETsoHE, a citizen of the United States of America, and resident of Yonkers, in the count of Westchester", in the State of New York, ave invented a certain new and useful Improvement in Rotary Pumps or Compressors, of which the following is a true and exact description, reference being had to the accompanying drawings, which form a part thereof.

My invention relates to rotary pumps of the kind provided with a rotary eccentric ring piston having an extension which serves as a partition between the admission and discharge ports of the `pump and the object of my improvements is to ldesign a pump of this kind which will be especially suitable for use as a dry air pump to evacuate air' from condensers, especially such condensers as are used in connection with steam turbines in which the vacuum created is very great, corresponding for instance to an absolute presvsure of a half-inch mercury column. As the air has to be compressed and discharged into the atmosphere, the pressure of which cor'- responds to Aa-th'irty inch mercury column, the ratio' of the two pressures areas one to sixty. In practice it has been found that in pumps or` compressors used for this class of work. the final temperature which is a natural functionof the pressure ratio is so high, that the lubrication used in the compressor with the natural injury to the wearing surfaces of the pump. Obviously the disadvantages noted 'can beover-v come by somewhat raising the initial pres.- sure' on the admission side of the pum withvout affecting thepressure in the con ensers for instance, an mcrease in the pressure on the admission side of the pump'of only one half inch of mercury would reduce the ratio of pressure to from one to thirty and the temperature due to compression accordingly. In my construction I provide for the closing of the admisslon port after the cylinder has received its full charge of air and for the subsequent increase of ressure in the air to be compressed,.by ma 'ng use of the back flow of compressed air from the clearance spaces of the pump and from the receiving chamber through the discharge` valves before these are seated. This will raise the initial pressure to a point which' will no longer result i n the creation of an injurious temperature 1n the pump'cylmder Ywall surface of the 'atthe end of compression of the air, and

my invention yhas particularly todo with the provision of a simple valve structure opening under the pressure of the fluid in the compressor and closing at the end of the side of a twin cylindercompressor taken on e the sectional line 1-1 of Fig. 2.

Fig. 2 is a side elevation of the compressor hown partly in section 'on the line 2 2 of Fig. 3 is an enlarged sectional view of the valve construction, and f y Fig. 4 a face view of this valve construction.

A and A indicate two compressor cylinders formed in the same casting and closed by 'face plates A2 and A2. B lndicates the periphery of the compressor cylinder interrupted at B and B2 to give clearance to the piston extension. C is a segmental cylindri. cal bearing surface formed in a cylinder casing. `D is the admission chamber .of the compressor having anl admission port D which, as shown, enters the admission side of the pump through an opening in the cylindrical bearing C. E is the delivery4 chamber of the pump having, as shown,van opening closed by a faceplate M. F is the pump extending from the point B2 of the cylinder to one side of the bearing surface C, the form in this wall must be such as to give clearance to the pist0n extension, to be described, which is shown in Fig. 1 in the Aposition of closest aproach to this wall. A portion of this wall llis ractically straight and through this wall form delivery ports indicated at E which are preferably in ring form, .as shown, and open into the delivery chamber E. G is the driving shaft of the compressor having secured to its eccentrics G on which are vthe eccentric rmg pistons H formed adapted l for its most advantageous use in y Aso with extensions Hfv which form partitions between the admission and delivery ports' remaining closed untll the piston has resumed contact with the periphery of its cylinder atA B. As shown, the oscillatory member has a clearance provided between the portion I and the valve I2 and a port C is formed through the wall C extending into the admission chamber D.

J in Fig. 3 indicates the valve for closing the delivery ports E. It is made in the form of an annular ring with a peripheral fiange J and is held in place and prevented from moving too far from its seat by an elastic abutment plate K secured in place by a bolt L and preferably formed in a series of tongues o-r wings by having formed in its periphery K o enings through its edges as indicated at 2.

In operation the air `from the compressor asses through the chamber D and the port until the pump chamber is fully charged which occurs immediately before the parts reach the position shown in Fig. l at which point the piston G is about to leave contact with the point B2 on the cylinder periphery and valve I? closes the ladmission port. further movement of 4the piston permits back flow of the air from the clearance spaces and also from the receiver E, the air flowing backward causing the valves J to close the ports E after a small amount of compressed air has passed back into the cylinder. The back flow of the compressed air from the receiver and the clearance spfaces will be such as to raise` the pressure of the air in the compressor to such a point as may be desired.

Durin the compression stroke of the piston whic `begins when the piston comes in contact with the periphery ofthe cylinder at B the air is compressed until this pressure equals that in the receiver E after which the valves lJ open freely permitting the escape of the air into the receiver.

The special construction of the valves J with the peripheral flanges J is suchas to greatly strengthen these valves and prevent the occurrence of such breakage perforations as has been found liable to occur with the use of thin unflan'ged plates. The flan e J also serves in connection with the flexib e abutment K to center and hold the valve in proper position.

ton extension forming a While `ny invention has been especially designed and is especially adapted for such uses as have been indicated it is obviously capable of other useful employment and while the special construction of the pump indicated is, I believe, exceedingly meritorious it is obvious 'that my invention can also be applied to modified forms of rotary piston pumps.

I-Iaving now described my invention, what I claim as newand desire to secure by Letters Patent, is:

1. In combination with a rotary pump having a rotary eccentric ring piston and a piston extension forming a partition between the admission and exhaust ports, a valve for closing the admission port, means for moving said `valve whereby it closes said port during the period when the piston is out of contact with itscylinder and leaves the port open at all other times and a valve for closingthe .delivery port opening under the pressure of the fluid in the pump and closing with the back flow when said pressureceases. v

`2. In4 combination with a rotary pump having a rotary eccentric ring piston, a pispartition between the admission and .exhaust pprts of the pump,an oscillatory member moving in a segmental cylindrical bearing to onev side of which the piston extension is hinged. and a wall section extending from the periphery of the pump cylinder to one end of the segmental bearing, an admission valve having means for closing it during the period when the piston is out of contact with its cylinder, one or more delivery ports formed through the wall section aforesaid and valves Vfor closing said delivery ports opening under the pressure of the fluid in the pump and closing with the back flow when said pressure ceases.

3. In combination with a rotary pump having'arotary eccentric ring piston, a piston extension forming a partition between the admission and exhaust ports of the pump, an oscillatory member moving in a se ental cylindrical bearing to one side of which the piston extension is hinged and a wall section extending from the periphery of the plump cylinder to one end of the "segmental bearing, an admissionvalve-moving with the oscillatory member and acting to close the admission portvduring the period when the piston is out of contact with the periphery of its cylinder, one or more delivery ports formed through the wall section aforesaid and valves for closing said delivery ports .opening under the pressure of the fluid in thepump and closing with the back flow when said pressure ceases.

GUSTAN B. PETSCHE. 

